|
  |
    |
This ecoregion includes most of the southern Canadian Shield in Ontario and Quebec. The shield, in fact, principally defines the southern boundaries of this ecoregion. It lies north and west of the St. Lawrence Lowlands except for a disjunct section comprised of the Adirondack Mountains in upper New York State. Having a humid mid-boreal ecoclimate in the northwest and a humid high cool temperate ecoclimate in the Algonquin area, the mean annual temperature ranges from 1.5°C to 3.5°C, increasing toward the south. The mean summer temperature of this region is 15°C, and the mean winter temperature ranges from -8.5°C to -11°C. Temperatures are slightly cooler in the southern Laurentians. Mean annual precipitation ranges from 800-1000 m; however, along the shores of Lake Superior and Georgian Bay, and between Quebec City and the Saguenay River, annual precipitation is in excess of 1000 mm. In general, this ecoregion experiences warm summers and cold, snowy winters (ESWG 1995). The Ontario part of this ecoregion is underlain by massive, crystalline, acidic, Archean bedrock forming undulating, broadly sloping uplands and lowlands with outcroppings. The Cobalt Plain in the northeast section of the Ontario portion is composed of flat-lying clastic sediments with ridges and hills formed by gabbro sills or granitic rock inliers. The Southern Laurentians in Quebec are composed mainly of Precambrain granites and gneisses, and are incised by a number of southward-draining rivers through highlands (ESWG 1995). The characteristic mixed forests of this ecoregion are distinct from the predominantly deciduous forests to the south and the cooler boreal forests to the north. In the northern reaches and in the Lac Temiscamingue area, the forests transition into a more predominantly boreal forest characteristic of ecoregions to the north, although on warmer, better drained sites, deciduous species dominate.
Mixedwood forests characterize this region and include white spruce (Picea glauca), balsam fir (Abies balsamea), quaking aspen (Populus tremuloides), paper birch (Betula papyrifera) and yellow birch (B. allegheniensis). Red (Pinus resinosa), white (P. strobus) and jack pine (P. banksiana) occur on drier sites in the northwest. To the south, in the Algonquin area, the mixedwood forest is characterized by stands of sugar maple (Acer saccharum), yellow birch, eastern hemlock (Tsuga canadensis)and eastern white pine, with beech (Fagus grandifolia) appearing on warmer sites. Poorly drained areas support tamarack (Larix laricina) and eastern white cedar (Thuja occidentalis), with black spruce (Picea mariana) in the north, and red maple (Acer rubrum) and black ash (Fraxinus nigra) in the Algonquin area. (ESWG 1995). Wetlands occur throughout the ecoregion, usually in association with river systems and along parts of the Georgian Bay shoreline. Moose (Alces alces), lynx (Lynx canadensis), black bear (Ursus americanus), snowshoe hare (Lepus americanus), wolf (Canis lupus), coyote (Canis latrans), white-tailed deer (Odocoileus virginianus), American black duck (Anas rubripes), wood duck (Aix sponsa), hooded merganser (Lophodytes cucullatus), and pileated woodpecker (Dryocopus pileatus) throughout, with chipmunk (Tamias striatus), mourning dove (Zenaida macroura), cardinal (Cardinalis cardinalis), and wood thrush (Hylocichla mustelina) in the Lake Nipissing-Algonquin area. The Southern Laurentians provide habitat for fewer animal species (ESWG 1995). Forest species assemblages are highly influenced by drainage characteristics and topography. Fire is an important disturbance regime in the ecoregion on spatial scales of up to 1,000 km2, particularly in the northern parts of the ecoregion. Elsewhere, smaller fires are more common. This is the southern limit of timber wolves in eastern North America and there are emerging plans to reintroduce wolves into such areas as the Adirondacks. Recently, eastern cougar (Felis concolor) sightings have been increasing in this ecoregion. The most widespread old-growth red and white pine stands remaining in the world and one of the largest remaining areas of old-growth forest in the northeastern United States, Five Ponds Wilderness, is found here. A large percentage of the Great Lakes watershed headwaters remain as relatively intact (rare on a continental scale). Habitat Loss It is estimated that only 10 percent of the ecoregion remains as intact habitat. Much of the area has been highly fragmented by forestry activities, settlements, summer homes and cottages, ski facilities and agriculture. Remaining Blocks of Intact Habitat
Degree of Fragmentation The ecoregion is highly fragmented by public roads, logging roads, large scale logging, and settlement patterns. Degree of Protection
Types and Severity of Threats The timber industry continues to be very active in the ecoregion, particularly in the Canadian portion. There is increased mining potential throughout and tourism is beginning to create significant impacts in parts of the ecoregion.
 Relationship to other classification schemes This mixedwood forest region is composed of the Lake Temiskaming lowland, the southern Laurentians, and the Algonquin-Lake Nipissing area (TEC ecoregions 97, 98, and 99) (ESWG 1995). Because this ecoregion is a transition zone, it is characterized by a variety of forest types, including the Laurentide-Onatchiway (1a), Chibougamau-Natashquan (1b), Gouin (3) and Missinaibi-Cabonga (7) within the Boreal forest region. In the Great Lakes-St. Lawrence forest region, sections include the Laurentian, Algonquin-Pontiac, Middle Ottawa, Georgian Bay, Sudbury-North Bay, Saguenay, Haileybury Clay, Temagami, and Algoma (4a, 4b, 4c, 4d, 4e, 7-10) (Rowe 1972). Prepared by: K. Kavanagh, L. Gratton, M. Davis, S. Buttrick, N. Zinger, T. Gray, M. Sims, G. Mann. This text was originally published in the book Terrestrial ecoregions of North America: a conservation assessment from Island Press. This assessment offers an in-depth analysis of the biodiversity and conservation status of North America's ecoregions. All text by World Wildlife Fund © 2001 For more general information on this ecoregion, go to the WildWorld version of this description.
|
More Photos